Batboard

I know, I know, I want my cake and eat it too.

Any thoughts on cobbling together, without breaking the bank, (i.e. not a FutureCom) a solution for an in-band RICK from a conventional mobile to a trunked mobile? Talk permit tones aren't very critical here, although they'd be nice, the system has plenty of capacity and the trunked mobile's antenna will be external with a clear LOS to the prime site. Problem is some buildings on site with very poor coverage, would like to add a conventional channel to their 800MHz portable, cross it over the to the trunked mobile and onto the trunk system.

Trunked system is a smartnet, FWIW, customer has a large mix of mobiles from GTX's to Maxtracs to XTL1500s to TRBOs. Looking to make this happen for less than $3000 per installation. Have an expected need for 10-12 of these setups, all will have good isolation from the inside to the outside (hence the need for this setup).

I did this on 900 MHz with a Pyramid 200 and a Ericsson Orion. Used a conventional channel at 939.xxx simplex and crossed to a EDACS system highest mobile TX frequency was 898.500 or so. Ran the 200 at 1 watt to a portable BNC antenna directly attached to the 200. Mobile was 30 watts to elevated feed on top of the van. Worked very well. Even put the 200 on a outside mag mount 1/4 wave and still worked well.

I know the SVR200 is a active device but a RICK with a decent radio should work fine. The issue will be max frequency separation between your simplex RX freq and the TRS TX freq. In other words, use the highest in-band simplex freq (like 8TAC94D if you can...) and it should work OK.

Reading further, this is going in a mobile or fixed location? Looks like fixed the more I read. Did that too but it was way over engineered using a MDX for a link radio to the TRS, a Kenwood TKR901 on 900 conventional and a S-Com 7K repeater panel to tie it all together to form a cross-mode system.

Is this in-building fixed or vehicle-mounted? I can think of ways to make both scenarios work, with the fixed site installation obviously being easier.

Obviously frequency separation is the critical element here. If this is a non-rebanded NPSPAC system with 866-869 frequencies or a mix of 856-861 and 866-869, use 851 MHz. If it's rebanded NPSPAC with 851-854, use 860.xxxx something. If it's rebanded NPSPAC with a mix of 851-854 and 856-861, then you may have a problem.

For a fixed installation, you can stick a super high-gain Yagi on the roof and point it to the site, then either run coax down to the radio or run audio down to the link radio location if the distance is too great. Then use a 1/4-wave stinger or a ceiling-mount 800 antenna inside located central to where you need RF coverage. Building shielding combined with the high gain on the trunking output should be adequate to prevent desense. Obviously the trunking input TX isn't going to interfere with the link radio RX due to the 45 MHz or greater frequency separation, but the link TX could certainly interfere with the trunking output RX.

For a mobile installation, I'd start by sticking my link radio antenna underneath the vehicle and as physically far away from the trunking radio's antenna as possible and see if that provided adequate separation. If not, I'd use a 1 MHz cavity filter on the link radio and a notch filter on the trunking radio tuned to the link radio's frequency.